Human Papillomavirus Vaccination Schedule: Adherence Among Commercially Insured Adolescents and Young Adults in the United States, 2011-2017.

Objectives. To determine rates of human papillomavirus (HPV) vaccine adherence to the 2011 and 2016 Advisory Committee for Immunization Practices (ACIP) recommendations in the United States.Methods. We conducted a retrospective cohort study by using the 2011 to 2017 Marketscan data for beneficiaries aged 9 to 26 years who had at least 1 claim for HPV vaccination between January 1, 2011, and January 1, 2017. According to the 2011 ACIP recommendation, adherence is defined as 30 to 90 days between the first and second vaccination and 168 to 212 days between the first and third vaccination. According to the 2016 recommendation, preadolescents are classified as adherent if they had 2 claims of vaccination within 168 to 212 days. We calculated proportions of completion and adherence by recommendation.Results. Among patients classified under the 2011 ACIP recommendation (n = 2 164 096), 8.3% completed all 3 doses of the vaccine series. Of those who completed, 69.6% were considered adherent to the recommended schedule. Completion and adherence increased to 9.6% and 70.8%, respectively, among patients who were classified under the 2016 ACIP recommendation.Conclusions. Simpler recommendations lead to better adherence to the HPV vaccination schedule.